So start by dividing up the 74 pebbles into 25 piles as evenly as you can

24 piles will have 3 pebbles each and 1 pile will have 2 pebbles

One of the piles has more pebbles than any other piles

lets take 1 pebble is a pile that have 3 pebbles and put it in another pile with 3 pebbles

now one pile will have 4 pebbles, 23 piles will have 3 pebbles each and 2 piles will have 2 pebbles each

the pile with 4 pebbles has more pebbles than any other pile since 4 > 3 and 4 > 2

thus the least amount of pebbles to make this pile is 4.