Limits Continuity and Differentiability

If $f$ is a real valued differentiable function satisfying $\left| {f\left( x \right) - f\left( y \right)} \right|$ $\le {\left( {x - y} \right)^2}$, $x, y$ $\in R$ and $f(0)$ = 0, then $f(1)$ equals