#include <stdio.h>
int main()
{
    int i,n,m,k,x,y;
    int a[100001][2];
    int aa[75000000];
    
    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--)
    {
        x=a[i][0];
        y=a[i][1];
        if (k>=x) k+=y-x+1;        
    }
    if (k>n) printf("0\n");
    else printf("%d\n",k);
    return 0;    
}