1 /************************************************************** 2     Problem: 1691 3     User: rausen 4     Language: C++ 5     Result: Accepted 6     Time:336 ms 7     Memory:3428 kb 8 ****************************************************************/ 9  10 #include <cstdio>11 #include <algorithm>12 #include <set>13  14 using namespace std;15 typedef long long ll;16 const int N = 100005;17  18 struct data{19     int x, y;20 }a[N], b[N];21 inline bool operator < (const data &a, const data &b){22     return a.y > b.y;23 }24 multiset <int> s;25 multiset <int> :: iterator it;26 int n, m, i, j = 1, x;27 char ch;28 ll ans;29  30 inline unsigned int read(){31     x = 0;32     ch = getchar();33     while (ch < ‘0‘ || ch > ‘9‘)34         ch = getchar();35  36     while (ch >= ‘0‘ && ch <= ‘9‘){37         x = x * 10 + ch - ‘0‘;38         ch = getchar();39     }40     return x;41 }42  43 int main(){44     n = read(), m = read();45     for (i = 1; i <= n; ++i)46         a[i].x = read(), a[i].y = read();47     for (i = 1; i <= m; ++i)48         b[i].x = read(), b[i].y = read();49     sort(a + 1, a + n + 1);50     sort(b + 1, b + m + 1);51     for (i = 1; i <= n; ++i){52         while (a[i].y <= b[j].y && j <= m)53             s.insert(b[j].x), ++j;54         it = s.lower_bound(a[i].x);55         if (it == s.end()){56             printf("-1\n");57             return 0;58         }59         ans += *it;60         s.erase(it);61     }62     printf("%lld\n", ans);63     return 0;64 }