#include<stdio.h>
#include<algorithm>
#define maxn 100005
using namespace std;

int n,m,K,cnt;
int a[maxn],b[maxn];

void read()
{
    scanf("%d%d%d",&n,&m,&K);
    for(int i=1;i<=m;i++) scanf("%d %d",&a[i],&b[i]);
}

void solve()
{
    cnt=K;
    for(int i=m;i;i--)
     if(a[i]<=cnt) cnt=cnt+b[i]-a[i]+1;
}

int main()
{
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);

    read();
    solve();
    printf("%d",cnt);

    fclose(stdin);
    fclose(stdout);
    return 0;
}