Building Teams

input/code.cpp: In function 'int main()':
input/code.cpp:51:2: error: expected '}' at end of input
   51 | }
      |  ^
input/code.cpp:5:11: note: to match this '{'
    5 | int main(){
      |           ^

#include <bits/stdc++.h> 
using namespace std;
#define REP(i,a,b) for (int i = a; i < b; i++)

int main(){
    int n;
    int m;
    cin>>n>>m;
    bool impossible = false;

    vector<int> adj[n];
    REP(i,0,m){
        int a;
        int b;
        cin>>a>>b;
        a--;b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }


    queue<int> q;
    bool visited[n];
    int distance[n]; 

    REP(i,0,n){
    if (visited[i]) continue;
    else{
    visited[i] = true;
    distance[i] = 0;
    q.push(i);
    while (!q.empty()) {
        int s = q.front(); q.pop();
        // process node s
        for (auto u : adj[s]) {
            if (visited[u]&&(distance[u]==distance[s])) {impossible= true; break;break;};
            if (visited[u]&&(distance[u]!=distance[s])) continue;
            visited[u] = true;
            distance[u] = (distance[s]+1)%2;
            q.push(u);
        }
        }
    }

    REP(i,0,n){
        cout<<(distance[i]+1);
    }


    return 0;
}