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