#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int x[100001],y[100001];
int getINT()
{
    char c;
    int nr=0;
    c=getchar();
    while(isdigit(c))
    {
        nr=nr*10+c-'0';
        c=getchar();
    }
    return nr;
}
int main()
{
    int i,n,m,k,pos;
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    n=getINT();
    m=getINT();
    k=getINT();
    for(i=1; i<=m; i++){
        x[i]=getINT();
        y[i]=getINT();
    }
    //scanf("%d%d",&x[i],&y[i]);
    pos=k;
    for(i=m; i>=1; i--)
        if(x[i]<=pos){
            pos+=(y[i]-x[i]+1);
            if(pos>n)
                break;
        }
    if(i>=1)
        printf("0\n");
    else
        printf("%d\n",pos);

    return 0;
}