23 lines
387 B
C++
23 lines
387 B
C++
#include <bits/stdc++.h>
|
|
|
|
using namespace std;
|
|
const int N = 10010;
|
|
int b[N];
|
|
int l;
|
|
int m;
|
|
|
|
int cnt;
|
|
|
|
int main() {
|
|
scanf("%d %d", &l, &m);
|
|
while (m--) {
|
|
int u, v;
|
|
scanf("%d %d", &u, &v);
|
|
for (int i = u; i <= v; i++) b[i]++;
|
|
}
|
|
for (int i = 0; i <= l; i++)
|
|
if (b[i] == 0) cnt++;
|
|
|
|
printf("%d", cnt);
|
|
return 0;
|
|
} |