#include <bits/stdc++.h>   using namespace std;   const double PI = 2.0 * acos(0.0);   inline int getInt() {     int x;     scanf( %d , &x);     return x;   }   inline long long getLL() {     long long x;     scanf( %lld , &x);     return x;   };   inline int NUM(char c) { return (int)c - 48; }   inline char CHR(int n) { return (char)(n + 48); }   template <class T>   inline T MAX(T a, T b) {     if (a > b) return a;     return b;   }   template <class T>   inline T MIN(T a, T b) {     if (a < b) return a;     return b;   }   inline void OPEN(const string &s) {     freopen((s +  .in ).c_str(),  r , stdin);     freopen((s +  .out ).c_str(),  w , stdout);   }   map<string, int> score, sco, mis;   map<string, int> times;   int main() {     vector<string> v;     for (int k = 0, _n = (5); k < _n; k++) {       string A, B, C;       cin >> A >> B;       cin >> C;       for (int i = 0, _n = ((C).size()); i < _n; i++)         if (C[i] ==  : ) C[i] =    ;       stringstream ss(C);       int s, m;       ss >> s >> m;       if (s > m)         score[A] += 3;       else if (s < m)         score[B] += 3;       else {         score[A]++;         score[B]++;       }       sco[A] += s;       mis[A] += m;       sco[B] += m;       mis[B] += s;       v.push_back(A);       v.push_back(B);       times[A]++;       times[B]++;     }     sort((v).begin(), (v).end());     v.resize(unique((v).begin(), (v).end()) - v.begin());     string OTHER;     for (int i = 0, _n = ((v).size()); i < _n; i++) {       if (times[v[i]] == 2 && v[i] !=  BERLAND ) OTHER = v[i];     }     vector<pair<int, pair<int, pair<int, string> > > > sorted;     for (int d = (1), _b = (50); d <= _b; d++) {       for (int m = (0), _b = (50); m <= _b; m++) {         int s = m + d;         string A, B;         A =  BERLAND , B = OTHER;         score[A] += 3;         sco[A] += s;         sco[B] += m;         mis[B] += s;         mis[A] += m;         sorted.clear();         for (int i = 0, _n = ((v).size()); i < _n; i++) {           sorted.push_back(make_pair(               -score[v[i]],               make_pair(-sco[v[i]] + mis[v[i]], make_pair(-sco[v[i]], v[i]))));         }         sort((sorted).begin(), (sorted).end());         if (sorted[0].second.second.second ==  BERLAND  ||             sorted[1].second.second.second ==  BERLAND ) {           cout << s <<  :  << m << endl;           return 0;         }         score[A] -= 3;         sco[A] -= s;         sco[B] -= m;         mis[B] -= s;         mis[A] -= m;       }     }     cout <<  IMPOSSIBLE  << endl;     return 0;   }   