#include<stdio.h>

long long k,t,x,y,n,m,i;

struct nod
{ long long  x,y;
}a[100010];

int main()
{ 
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    
    scanf("%lld %lld %lld",&n,&m,&k);
    
    for(i=1;i<=m;i++) scanf("%lld %lld",&a[i].x,&a[i].y);
    for(i=m;i>=1;--i) if (a[i].x<=k) k+=a[i].y-a[i].x+1;
    printf("%lld\n",k);
    fclose(stdin);
    fclose(stdout);
    return 0;
}