#include <stdio.h>
#include <string.h>

#define MAX_M 100100

int A[MAX_M][2], K, N, M;

int main(void)
{
    freopen("stergeri.in", "rt", stdin);
    freopen("stergeri.out", "wt", stdout);

    int i, j, k;


    
    scanf("%d %d %d\n", &N, &M, &K);

    for(i = 1; i <= M; i++) scanf("%d %d\n", &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\n", K);

    return 0;
}