#include<bits/stdc++.h>
using namespace std;

int main(){

	int x,start,end,temp;
	vector<int> nums;
	vector<int> missing;
	string line;
	bitset<2001> valid;

	while(getline(cin,line)){
		stringstream ss;
		ss << line;
		while(ss >> x){
			nums.push_back(x);
		}
		bool ruler = true;
		bool perfect = true;
		valid.reset();
		for(int i = 0; i < nums.size()-1; i++){
			for(int j = i+1; j < nums.size(); j++){
				temp = abs(nums[i]-nums[j]);
				if(valid[temp]){
					ruler = false;
				}
				else
					valid[temp] = true;
			}
		}
		start = nums[0];
		end  = nums[nums.size()-1];
		if(ruler){
			for(int i = start; i < end + 1; i++){
				if(!valid[i] && i != 0){
					perfect = false;
					missing.push_back(i);
				}
			}
			if(perfect)
				printf("perfect\n");
			else{
				printf("missing ");
				for(int i = 0; i < missing.size(); i++){
					printf("%d ",missing[i]);
				}
				printf("\n");
			}
		}
		else{
			printf("not a ruler\n");
		}
		nums.clear();
		missing.clear();
	}
}