func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename T>   ostream& operator<<(ostream& s, vector<T>& v) {     s <<  { ;     for (int i = 0; i < int(v.size()); i++) s << (i ?  ,  :   ) << v[i];     return s <<  } ;   }   template <typename S, typename T>   ostream& operator<<(ostream& s, pair<S, T> const& p) {     return s <<  (  << p.first <<  ,  << p.second <<  ) ;   }   const long long INV2 = 500000004;   const long long INV3 = 333333336;   const long long MOD = 1000000007;   long long modexp(long long x, long long n) {     long long result = 1;     while (n) {       if (n % 2) {         result = (result * x) % MOD;         n--;       }       x = (x * x) % MOD;       n /= 2;     }     return result;   }   int main() {     int K;     bool even = false;     scanf( %d , &K);     long long sm = 2;     for (int k = 0; k < int(K); k++) {       long long a;       scanf( %lld , &a);       if (a % 2 == 0) even = true;       sm = modexp(sm, a);     }     sm = (sm * INV2) % MOD;     long long denom = (sm + MOD) % MOD;     if (even)       sm++;     else       sm--;     sm = (sm * INV3) % MOD;     sm = (sm + MOD) % MOD;     printf( %lld/%lld n , sm, denom);   }   