#include <stdio.h>
#include <stdlib.h>
int x[100001],y[100001];
int main()
{
    int i,n,m,k,pos;
    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",&x[i],&y[i]);
    pos=k;
    for(i=m; i>=1 && pos<=n; i--)
        if(x[i]<=pos)
            pos+=(y[i]-x[i]+1);
    if(i>=1)
        printf("0\n");
    else
        printf("%d\n",pos);

    return 0;
}