func_code_string: #include <bits/stdc++.h>   const unsigned long long inf = 1LL << 61;   const double eps = 1e-5;   using namespace std;   bool cmp(int a, int b) { return a > b; }   string itoa(long long a) {     string t =   ;     while (a > 0) {       t += (char)(a % 10 +  0 );       a /= 10;     }     string s =   ;     for (int i = t.size() - 1; i >= 0; i--) s += t[i];     return s;   }   long long atoi(string s) {     long long t = 1;     long long ans = 0;     for (int i = s.size() - 1; i >= 0; i--) {       long long b = (long long)(s[i] -  0 );       ans += b * t;       t *= 10;     }     return ans;   }   int main() {     int n, m;     while (cin >> n >> m) {       long long c = m + n;       string c1 = itoa(c);       string c2 =   ;       for (int i = 0; i < c1.size(); i++) {         if (c1[i] !=  0 ) c2 += c1[i];       }       long long cc = atoi(c2);       string a = itoa(n);       string b = itoa(m);       string a1 =   ;       string b1 =   ;       for (int i = 0; i < a.size(); i++) {         if (a[i] !=  0 ) a1 += a[i];       }       for (int j = 0; j < b.size(); j++) {         if (b[j] !=  0 ) b1 += b[j];       }       long long aa = atoi(a1);       long long bb = atoi(b1);       if (aa + bb == cc)         puts( YES );       else         puts( NO );     }     return 0;   }   