CodeForces 14B Young Photographer

#include<cstdio>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<cstdlib>
#include<iomanip>
#include<string>
#include<vector>
#include<map>
#include<string>
#include<iostream>
#include<algorithm>
using namespace std;
#define INF 0x3f3f3f3f
typedef long long ll;
#define Max(a,b) (a>b)?a:b
#define lowbit(x) x&(-x)

int main()
{
    int n,a[5005]={0},x,y,ans=INF,x0;
    scanf("%d%d",&n,&x0);
    for(int i=0;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        if(x>y)
            swap(x,y);
        for(int j=x;j<=y;j++)
        {
            a[j]++;
            if(a[j]==n)
            {
                if(abs(j-x0)<ans)
                    ans=abs(j-x0);
            }
        }
    }
    if(ans==INF)
        ans=-1;
    printf("%d\n",ans);
}