C++
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("O3")
#include<bits/stdc++.h>
using namespace std;
//#define INF 2147483647
#define INFL 9223372036854775807
#define pii pair<int,int>
#define F first
#define S second
#define mp make_pair
#define pb push_back
#define ll long long
#define ull unsigned long long
#define M 1000000007
#define FASTIO ios_base::sync_with_stdio(false);cin.tie(NULL); cout.tie(NULL);
#define take(x) scanf("%d",&x)
#define DE(x) printf("\ndebug %d\n",x);
#define vout(x) for(int i=0;i<x.size();i++) printf("%d ",x[i]);
#define pie acos(-1)
#define MOD 998244353
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int my_rand(int l, int r){return uniform_int_distribution<int>(l,r) (rng);}
struct pt {
int x, y, id;
};
struct cmp_x {
bool operator()(const pt & a, const pt & b) const {
return a.x < b.x || (a.x == b.x && a.y < b.y);
}
};
struct cmp_y {
bool operator()(const pt & a, const pt & b) const {
return a.y < b.y;
}
};
int n;
vector<pt> a;
long long mindist;
pair<int, int> best_pair;
void upd_ans(const pt & a, const pt & b) {
//double dist = sqrt((a.x - b.x)*(a.x - b.x) + (a.y - b.y)*(a.y - b.y));
long long dist = 1LL*(a.x - b.x)*(a.x - b.x) + 1LL*(a.y - b.y)*(a.y - b.y);
if (dist < mindist) {
mindist = dist;
best_pair = {a.id, b.id};
}
}
vector<pt> t;
void rec(int l, int r) {
if (r - l <= 3) {
for (int i = l; i < r; ++i) {
for (int j = i + 1; j < r; ++j) {
upd_ans(a[i], a[j]);
}
}
sort(a.begin() + l, a.begin() + r, cmp_y());
return;
}
int m = (l + r) >> 1;
int midx = a[m].x;
rec(l, m);
rec(m, r);
merge(a.begin() + l, a.begin() + m, a.begin() + m, a.begin() + r, t.begin(), cmp_y());
copy(t.begin(), t.begin() + r - l, a.begin() + l);
int tsz = 0;
for (int i = l; i < r; ++i) {
if (abs(a[i].x - midx) < mindist) {
for (int j = tsz - 1; j >= 0 && a[i].y - t[j].y < mindist; --j)
upd_ans(a[i], t[j]);
t[tsz++] = a[i];
}
}
}
int main(){
FASTIO;
int n;
cin>>n;
a.reserve(n);
for(int i=0;i<n;i++){
int x,y;
cin>>x>>y;
a.push_back({x,y});
}
t.resize(n);
sort(a.begin(), a.end(), cmp_x());
mindist = 1E20;
rec(0, n);
cout<<mindist;
}