Image of the identity element under a ring morphism

Prove that if $ϕ : R \to S$ is a surjective ring homomorphism between commutative rings with unity, then $ϕ (1_{R}) = 1_{S}$ .

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Prove that if $\phi:R\to S$ is a surjective ring homomorphism between commutative rings with unity, then $\phi(1_R)=1_S$.