View Compilation Error

0_0_25323795_2813.cpp: In function 'int f(int, int, int)':
0_0_25323795_2813.cpp:6:25: error: 'n' was not declared in this scope
 else return ((a * f(a,b,n - 1) + b * f(a,b,n - 2)) % 7);
                         ^