func_code_string: #include <bits/stdc++.h>   using namespace std;   const int mod = 1e9 + 7;   int inv[25];   long long a[25];   int power(int a, int b) {     int c = 1;     for (; b; b >>= 1) {       if (b & 1) c = (long long)c * a % mod;       a = (long long)a * a % mod;     }     return c;   }   int C(long long y, int x) {     if (y < 0 || x < 0 || y < x) return 0;     y %= mod;     if (y == 0 || x == 0) return 1;     int ans = 1;     for (int i = 0; i < x; i++) ans = (long long)ans * (y - i) % mod;     for (int i = 1; i <= x; i++) ans = (long long)ans * inv[i] % mod;     return ans;   }   int main() {     int n;     long long m;     long long ans = 0;     for (int i = 1; i <= 20; i++) inv[i] = power(i, mod - 2);     cin >> n >> m;     for (int i = 1; i <= n; i++) cin >> a[i];     for (int x = 0; x < (1 << n); x++) {       if (x == 0)         ans = (ans + C(n + m - 1, n - 1)) % mod;       else {         long long t = n + m;         int p = 0;         for (int i = 0; i < n; i++)           if ((x >> i) & 1) {             p++;             t -= a[i + 1];           }         t -= (p + 1);         if (p & 1)           ans = (ans - C(t, n - 1)) % mod;         else           ans = (ans + C(t, n - 1)) % mod;       }     }     cout << (ans + mod) % mod << endl;     return 0;   }   