How to Include a Random() number in Inno Setup?

How can i include an random number in a string in Inno Setup?

[Run]
#define rndH Random(24) 
#define rndM Random(60)

Filename: "schtasks"; \
  Parameters: "/Create /F /SC DAILY /ST {rndH}:{rndM} /RU SYSTEM /RL HIGHEST /TN ""Program Title"" /TR ""'{app}\program.exe'""";

When i try the code above, i get an error

[ISPP] Undeclared identifier: "Random"

Thanks