为什么#3答案对了但WA了

#include<bits/stdc++.h>
using namespace std;
string s[27]={"zero","one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen", "twenty","a","both","another","first","second","third"};
struct arr
{
    int a;
    int b;
}a[100];
bool cmp(arr x,arr y)
{
    if(x.b==y.b)return x.a<y.a;
    return x.b<y.b;
}
int main()
{
    string s1;
    int k=0,i;
    for(int i=0;i<6;i++)
    {
        cin>>s1;
        if(i==5)
        s1.erase(s1.length()-1,1);
        for(int j=0;j<=26;j++)
            if(s1==s[j])
        {
            int l=j;
            if(j==21||j==23||j==24)
                l=1;
            if(j==22j==25)
                l=2;
            if(j==26)
                l=3;
            int n=l*l;
            n%=100;
            a[k].a=n%10;
            a[k].b=n/10;
            k++;
        }
    }
    sort(a,a+k,cmp);
    int c;
    for(i=0;i<k;i++)
        if(a[i].b!=0)
        {
            c=0;
            break;
        }
        else if(a[i].a!=0)
        {
            c=1;
            break;
        }
     if(c==0)cout<<a[i].b<<a[i].a;
     else if(c==1) cout<<a[i].a;
     if(i==k)
     {
         cout<<"0";
         return 0;
     }

    for(i=i+1;i<k;i++)
    {
        cout<<a[i].b<<a[i].a;
    }


    return 0;
}