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    #include<cstdio>
    #include<cstring>
    #include<iostream>
    #include<cmath>
    #include<cstdlib>
    #include<map>
    using namespace std;
    #define ll long long
    map<int,int>m1;
    map<int,int>m2;
    map<int,int>m3;
    map<int,int>m4;
    int main()
    {
        int n,a,b,ans=0;
        scanf("%d",&n);
        for(int i=0;i<n;i++)
        {
            scanf("%d%d",&a,&b);
            ans+=m1[a];
            m1[a]++;
            ans+=m2[b];
            m2[b]++;
            ans+=m3[a+b];
            m3[a+b]++;
            ans+=m4[a-b];
            m4[a-b]++;
        }
        printf("%d\n",ans);
        return 0;
    }
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