func_code_string: #include <bits/stdc++.h>   using namespace std;   int Ask(string s) {     cout << s <<   n ;     cout.flush();     int diff;     cin >> diff;     if (diff == 0) exit(0);     return diff;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     if (fopen( input.txt ,  r )) {       freopen( input.txt ,  r , stdin);       freopen( output.txt ,  w , stdout);     }     int n = Ask( b ) + 1;     if (n > 300) {       string s =   ;       for (int i = 1; i < (int)n; ++i) s +=  a ;       Ask(s);     }     string s =   ;     for (int i = 1; i <= (int)n; ++i) s +=  b ;     int cur = Ask(s);     if (cur == n) {       s =   ;       for (int i = 1; i < (int)n; ++i) s +=  a ;       int ok = Ask(s);       assert(ok == 0);       return 0;     }     string ans = s;     for (int pos = 0; pos < (int)n; ++pos) {       s = ans;       s[pos] =  a ;       int tmp = Ask(s);       if (tmp < cur) ans[pos] =  a , cur = tmp;     }     return 0;   }   