#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;

string s;
char M[3][3];

int main(){
	while (cin >> s){
		char ans = 'd';
		REP(i, 3){
			if (s[0 + i] == 's')continue;
			if (s[0 + i] == s[3 + i] && s[3 + i] == s[6 + i])ans = s[0 + i];
		}
		for (int i = 0; i < 9; i += 3){
			if (s[i] == 's')continue;
			if (s[i] == s[i + 1] && s[i + 1] == s[i + 2])ans = s[i];
		}
		if (s[4] != 's'){
			if (s[0] == s[4] && s[4] == s[8])ans = s[0];
			if (s[2] == s[4] && s[4] == s[6])ans = s[2];
		}
		cout << ans << endl;
	}
}