#include<algorithm>
using namespace std;
int n,m,k,st[100001],dr[100001];
void solve(){
    int i;
    scanf("%d%d%d",&n,&m,&k);
    for(i=m; i; --i)
        scanf("%d%d",&st[i],&dr[i]);
    for(i=1; i<=m; ++i) 
        if(st[i]<=k)
            k+=(dr[i]-st[i])+1;
    printf("%d",k);}
int main(){
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    solve();
    return 0;}