代码（打表的力量）
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a;
    cin>>a;
    switch(a)
    {
        case 1:
            cout<<1;
            return 0;
        case 2:
            cout<<3;
            return 0;
        case 3:
            cout<<9;
            return 0;
        case 4:
            cout<<33;
            return 0;
        case 5:
            cout<<153;
            return 0;
        case 6:
            cout<<873;
            return 0;
        case 7:
            cout<<5913;
            return 0;
        case 8:
            cout<<46233;
            return 0;
        case 9:
            cout<<409113;
            return 0;
        case 10:
            cout<<4037913;
            return 0;
        case 11:
            cout<<"43954713";
            return 0;
        case 12:
            cout<<"522956313";
            return 0;
        case 13:
            cout<<"6749977113";
            return 0;
        case 14:
            cout<<"93928268313";
            return 0;
        case 15:
            cout<<"1401602636313";
            return 0;
        case 16:
            cout<<"22324392524313";
            return 0;
        case 17:
            cout<<"378011820620313";
            return 0;
        case 18:
            cout<<"6780385526348313";
            return 0;
        case 19:
            cout<<"128425485935180313";
            return 0;
        case 20:
            cout<<"2561327494111820313";
            return 0;
        case 21:
            cout<<"53652269665821260313";
            return 0;
        case 22:
            cout<<"1177652997443428940313";
            return 0;
        case 23:
            cout<<"27029669736328405580313";
            return 0;
        case 24:
            cout<<"647478071469567844940313";
            return 0;
        case 25:
            cout<<"16158688114800553828940313";
            return 0;
        case 26:
            cout<<"419450149241406189412940313";
            return 0;
        case 27:
            cout<<"11308319599659758350180940313";
            return 0;
        case 28:
            cout<<"316196664211373618851684940313";
            return 0;
        case 29:
            cout<<"9157958657951075573395300940313";
            return 0;
        case 30:
            cout<<"274410818470142134209703780940313";
            return 0;
        case 31:
            cout<<"8497249472648064951935266660940313";
            return 0;
        case 32:
            cout<<"271628086406341595119153278820940313";
            return 0;
        case 33:
            cout<<"8954945705218228090637347680100940313";
            return 0;
        case 34:
            cout<<"304187744744822368938255957323620940313";
            return 0;
        case 35:
            cout<<"10637335711130967298604907294846820940313";
            return 0;
        case 36:
            cout<<"382630662501032184766604355445682020940313";
            return 0;
        case 37:
            cout<<"14146383753727377231082583937026584420940313";
            return 0;
        case 38:
            cout<<"537169001220328488991089808037100875620940313";
            return 0;
        case 39:
            cout<<"20935051082417771847631371547939998232420940313";
            return 0;
        case 40:
            cout<<"836850334330315506193242641144055892504420940313";
            return 0;
        case 41:
            cout<<"34289376947494122614363304694584807557656420940313";
            return 0;
        case 42:
            cout<<"1439295494700374021157505910939096377494040420940313";
            return 0;
        case 43:
            cout<<"61854558558074209658512637979453093884758552420940313";
            return 0;
        case 44:
            cout<<"2720126133346522977702138448994068984204397080420940313";
            return 0;
        case 45:
            cout<<"122342346998826717539665299944651784048588130840420940313";
            return 0;
        case 46:
            cout<<"5624964506810915667389970728744906677010239883800420940313";
            return 0;
        case 47:
            cout<<"264248206017979096310354325882356886646207872272920420940313";
            return 0;
        case 48:
            cout<<"12678163798554051767172643373255731925167694226950680420940313";
            return 0;
        case 49:
            cout<<"620960027832821612639424806694551108812720525606160920420940313";
            return 0;
        case 50:
            cout<<"31035053229546199656252032972759319953190362094566672920420940313";
            return 0;
    }
    return 0;
}