Written by Carole Bayer-Sager and Toni Wine and made famous in 1965 by the Mindbenders (what a fantastic name for a band !). With a really nice girl-background-choir. In the eighties, Phil Collins also gave it a try. Well.
G, later modulates to A
Easy, but not a three-chord-song. Indeed very interesting chord progression with the root notes going up one step from F - Gm - Am - Bb - C and then back to F. I could repeat this theme forever. Before it gets boring, it modulates to G.