#include<stdio.h>
 
int n,m,k;
int st[100004][2];
 
int main()
{
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    scanf("%d%d%d",&n,&m,&k);
    for(int i=0;i<m;++i)scanf("%d%d",&st[i][0],&st[i][1]);
    for(int i=m-1;i>=0;--i)
        if(st[i][0]<=k)k+=st[i][1]-st[i][0]+1;
 
    printf("%d\n",k);
    return 0;
}