#include<cstdio>

int a[100002],b[100002];

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