How change rows value in a "Map loop" in R-studio?

Question

I have this dataframe:

df <- structure(list(a = c(2, 5, 90, 77, 56, 65, 85, 75, 12, 24, 52, 
32), b = c(45, 78, 98, 55, 63, 12, 23, 38, 75, 68, 99, 73), c = c(77, 
85, 3, 22, 4, 69, 86, 39, 78, 36, 96, 11), d = c(52, 68, 4, 25, 
79, 120, 97, 20, 7, 19, 37, 67), e = c(14, 73, 91, 87, 94, 38, 
1, 685, 47, 102, 666, 74)), class = "data.frame", row.names = c(NA, 
-12L))

and the script:

R <- Map(`+`, list(1:3), 0:3)
df_cum <- as.matrix(rep(NA, ncol(df)))
for (r in seq(R)) {
  for (f in seq(ncol(df))) {
    df_cum <- sapply(df[R[[r]],], function(x) (cumprod(1 + x) - 1)*100)
  }
}

I want to change all the first row values to "0", for each loop (1:3, 2:4, 3:5,...), before

df_cum <- sapply(df[R[[r]],], function(x) (cumprod(1 + x) - 1)*100)

I.e. for the first cicle 1:3 (df rows), the first row values change from "2, 45, 77, 52, 14" to "0, 0, 0, 0, 0".

How can I do? Thx