View Compilation Error

0_0_30425689_23292.cpp: In function 'u128 dfs(u128, u128, u128)':
0_0_30425689_23292.cpp:10:32: error: too few arguments to function 'u128 dfs(u128, u128, u128)'
     if(n>128) return (7*dfs(n/2)% mod + 18*a*(n/2)*(n/2) % mod) % mod;
                                ^
0_0_30425689_23292.cpp:8:6: note: declared here
 u128 dfs(u128 n, u128 a, u128 b) {
      ^