// 题意：输入5个整数，按照某种顺序排列后依次进行+, -或者*，使得最终结果为23。判断是否有解
// 算法：回溯
1 #include <cstdio> 2 #include <cstdlib> 3 #include <cctype> 4 #include <cstring> 5 #include <cmath> 6 #include <ctime> 7 #include <string> 8 #include <vector> 9 #include <map> 10 #include <set> 11 #include <algorithm> 12 #include <iostream> 13 using namespace std; 14 typedef long long ll; 15 int a[10]; 16 int mark[10]; 17 bool flag; 18 19 int Sum( int x, int ans, int m ) 20 { 21 if( x == 0 ) 22 return ans + m; 23 if( x == 1 ) 24 return ans - m; 25 return ans * m; 26 } 27 28 void dfs( int x, int ans ) 29 { 30 if( flag ) 31 return; 32 if( x == 5 ) 33 { 34 if( ans == 23 ) 35 flag = true; 36 return; 37 } 38 for( int i = 0; i < 5; ++i ) 39 if( !mark[i] ) 40 { 41 mark[i] = 1; 42 dfs( x+1, Sum( 0, ans, a[i] ) ); 43 dfs( x+1, Sum( 1, ans, a[i] ) ); 44 dfs( x+1, Sum( 2, ans, a[i] ) ); 45 mark[i] = 0; 46 } 47 } 48 49 void solve() 50 { 51 for( int i = 0; i < 5; ++i ) 52 { 53 memset( mark, 0, sizeof( mark ) ); 54 mark[i] = 1; 55 dfs( 1, a[i] ); 56 } 57 } 58 59 int main() 60 { 61 while( ~scanf( "%d%d%d%d%d", &a[0], &a[1], &a[2], &a[3], &a[4] ) && a[0]+a[1]+a[2]+a[3]+a[4] ) 62 { 63 flag = false; 64 solve(); 65 if( flag ) 66 puts( "Possible" ); 67 else 68 puts( "Impossible" ); 69 } 70 return 0; 71 }