#include<stdio.h>

int i, m, n, k, a[100002][2];

int main (){
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);

    scanf("%d %d %d", &n, &m, &k);
    for (i = 1; i <= m; i++)
        scanf("%d %d", &a[i][0], &a[i][1]);

    for (i = m; i >= 1; i--)
        if (a[i][0] <= k) k += a[i][1] - a[i][0] + 1;

    printf("%d", k);
    return 0;
}