func_code_string: #include <bits/stdc++.h>   int nextInt() {     int x;     scanf( %d , &x);     return x;   }   double nextDouble() {     double x;     scanf( %lf , &x);     return x;   }   long long nextLong() {     long long x;     scanf( %I64d , &x);     return x;   }   char nextChar() {     char x;     scanf( %c , &x);     return x;   }   void newLine() { printf(  n ); }   long long powM(long long a, long long b, long long MOD) {     long long x = 1, y = a;     while (b > 0) {       if (b % 2 == 1) {         x = (x * y);         if (x > MOD) x %= MOD;       }       y = (y * y);       if (y > MOD) y %= MOD;       b /= 2;     }     return x;   }   long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }   long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); }   int countSetBits(long long n) {     int ans = 0;     while (n != 0) {       n -= (n & -n);       ++ans;     }     return ans;   }   long long mod = 1000000007;   long long mod2 = 1000000009;   const int N = 1100;   const int M = 111;   const int LOG = 21;   const long long INF = 1e18;   const long double EPS = 1e-6;   const long double PI = 2 * acos(0);   using namespace std;   int a[N], b[N];   int main() {     int n = nextInt();     int m = nextInt();     int d = 0;     bool ok = true;     for (int i = 0; i < m; i++) {       int x = nextInt(), y = nextInt();       a[x] += 1;       a[y + 1] -= 1;     }     for (int i = 1; i <= n; i++) a[i] += a[i - 1];     for (int i = 1; i <= n; i++) {       if (a[i] != 1) {         cout << i <<     << a[i] << endl;         ok = false;         break;       }     }     if (ok) puts( OK );     return 0;   }   