#!/bin/sh
[ $# -eq 0 ] && sum="$(cat)" || sum="$1"
sum="$(echo "$sum" | tr -dc '[:digit:]')"
if [ -z "$sum" ] ; then
	echo "error: no input number"
	exit 1
fi

fmt() {
	# printf '%d:%02d:%02d\n' $@ | sed -e 's/^0\{2,\}//'
	printf '%02dh%02dm%02ds\n' $@ | sed -e 's/00s$//' -e 's/^\(00.\)\+//' -e 's/^0\+//'
}

fmt $(bc <<EOF
sum = $sum
seconds = sum % 60
sum = (sum - seconds) / 60
minutes = sum % 60
sum = (sum - minutes) / 60
hours = sum
print hours," ",minutes," ",seconds
EOF
)