func_code_string: #include <bits/stdc++.h>   using namespace std;   long long bigmod(long long b, long long p, long long m) {     if (p == 0) return 1;     long long my = bigmod(b, p / 2, m);     my *= my;     my %= m;     if (p & 1) my *= b, my %= m;     return my;   }   int setb(int n, int pos) { return n = n | (1 << pos); }   int resb(int n, int pos) { return n = n & ~(1 << pos); }   bool checkb(int n, int pos) { return (bool)(n & (1 << pos)); }   struct info {     int x, y, idx;     info() {}     info(int _x, int _y, int _idx) {       x = _x;       y = _y;       idx = _idx;     }     bool operator<(const info &p) const {       if (y == p.y)         return x < p.x;       else         return y < p.y;     }   };   info ara[200005];   bool taken[200005];   int n;   int last[2];   bool fuck() {     int i;     last[0] = last[1] = -1;     for (i = 1; i <= n; i++) {       if (last[0] > last[1]) swap(last[0], last[1]);       if (ara[i].x > last[1]) {         last[1] = ara[i].y;         continue;       }       if (ara[i].x > last[0]) {         last[0] = ara[i].y;         continue;       }       return 0;     }     return 1;   }   int main() {     int x, y, i;     scanf( %d , &n);     for (i = 1; i <= n; i++) {       scanf( %d %d , &x, &y);       ara[i] = info(x, y, i);     }     sort(ara + 1, ara + n + 1);     bool f = fuck();     if (f)       puts( YES );     else       puts( NO );     return 0;   }   