View Compilation Error

0_0_36644452_12508.cpp: In function 'void solve()':
0_0_36644452_12508.cpp:68:17: error: 'key' was not declared in this scope
                 key=a*G[i][k1]*G[i][k1]+c*G[i][k1];
                 ^
0_0_36644452_12508.cpp:72:17: error: 'key' was not declared in this scope
                 key=a*G[i][k2]*G[i][k2]+c*G[i][k2];
                 ^