ZOJ_1241

#include <cstdlib>
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
inline void cal(int a, int b, int c, char ch)
{
float result = 0.0;
if(c == -1)
result = sqrt(a * a + b * b);
else
result = sqrt(c * c - b * b);

if(c == -1)
c = result;
else
(a == -1) ? a = result : b = result;

if(a + b < c)
cout << "Impossible." << endl;
else
cout << ch << " = " << setprecision(3) << fixed << result << endl;

cout << endl;
}
int main(int argc, char *argv[])
{
//freopen("input.txt", "rt", stdin);
//freopen("output.txt", "wt", stdout);

int a, b, c;
int index = 1;
while(cin >> a >> b >> c &&( a != 0 && b != 0 && c != 0))
{
cout << "Triangle #" << index++ << endl;

if(a == -1)
cal(a, b, c, 'a');
else if(b == -1)
cal(b, a, c, 'b');
else
cal(a, b, c, 'c');
}
return EXIT_SUCCESS;
}